2026/02/24

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2026-02-24 22:57:07 +0100 <tomsmeding> that's probably easiest, yes (use ghcup)
2026-02-24 22:56:55 +0100 <Guest81> So i need ghci. Thanks all.
2026-02-24 22:55:48 +0100 <tomsmeding> ghci does quite a bit more than just an interpreter for basic expressions, and "learn you a haskell" assumes ghci
2026-02-24 22:55:46 +0100 <mauke> a = [1,2,3] is not an expression
2026-02-24 22:55:35 +0100 <tomsmeding> it is an interpreter, but not ghci
2026-02-24 22:55:12 +0100ChaiTRex(~ChaiTRex@user/chaitrex) ChaiTRex
2026-02-24 22:55:10 +0100 <Guest81> OK so basically "Try it!" is not a true interpreter.
2026-02-24 22:55:02 +0100 <geekosaur> probably just hint
2026-02-24 22:55:00 +0100 <monochrom> Who writes 1000 lines of code on a REPL anyway? Be realistic.
2026-02-24 22:54:51 +0100ChaiTRex(~ChaiTRex@user/chaitrex) (Remote host closed the connection)
2026-02-24 22:54:33 +0100astra(sid289983@id-289983.hampstead.irccloud.com)
2026-02-24 22:54:32 +0100prdak(~Thunderbi@user/prdak) (Ping timeout: 268 seconds)
2026-02-24 22:54:31 +0100 <tomsmeding> play.haskell.org is not a repl, though :)
2026-02-24 22:54:20 +0100 <tomsmeding> apparently it accepts only full expressions
2026-02-24 22:54:19 +0100astra(sid289983@user/amish) (Server closed connection)
2026-02-24 22:54:18 +0100 <monochrom> But play.haskell.org is better.
2026-02-24 22:54:07 +0100 <tomsmeding> ah yes, that does work Guest81 ^
2026-02-24 22:53:51 +0100 <monochrom> "let a = [1,2,3] in length a"
2026-02-24 22:53:35 +0100 <monochrom> Oh that. Sorry!
2026-02-24 22:53:23 +0100 <tomsmeding> monochrom: we're talking about the "Try it!" thing on haskell.org, which is stupid and broken
2026-02-24 22:53:12 +0100 <monochrom> "let a = [1,2,3]" also works for me.
2026-02-24 22:53:06 +0100 <tomsmeding> there's https://play.haskell.org if you want to upgrade to writing a full program (which doesn't have to be complicated!); otherwise, either install ghci, or there may be some other online repl
2026-02-24 22:52:47 +0100 <monochrom> "a = [1,2,3]" works for me.
2026-02-24 22:52:32 +0100 <EvanR> "interesting"
2026-02-24 22:52:21 +0100 <Guest81> <no location info>: not an expression: ‘let a = [1,2,3]’
2026-02-24 22:52:20 +0100 <Guest81> no go: let a = [1,2,3]
2026-02-24 22:52:08 +0100 <tomsmeding> it doesn't there
2026-02-24 22:52:02 +0100 <EvanR> a = [1,2,3] ought to work in ghci and at top level?
2026-02-24 22:51:55 +0100 <tomsmeding> that "Try it!" prompt on haskell.org is not a proper haskell interpreter
2026-02-24 22:51:40 +0100 <Rembane> Guest81: Try a let a = [1,2,3]
2026-02-24 22:51:20 +0100 <Guest81> I am reading "learn you a Haskell ..." and I am using interactive on the haskell.org homepage. But when I input a simple equality such as "a = [1,2,3]" is get a parse error. What am I doing wrong?
2026-02-24 22:51:08 +0100 <lantti> I'm in the process of re-evaluating that assumption :)
2026-02-24 22:50:48 +0100 <lantti> I suspected the printing because I realized there is an analytic solution to the actual problem and generating the lists is just some math operations and [1..xyz]
2026-02-24 22:50:44 +0100 <mauke> back when I did SPOJ, I got significant time improvements by bypassing stdio
2026-02-24 22:50:36 +0100 <tomsmeding> maybe in this tight loop that's true
2026-02-24 22:50:29 +0100 <tomsmeding> (that's a claim)
2026-02-24 22:50:28 +0100 <EvanR> i was going to say C is the one where you are sometimes trying to deduce how slow printing is
2026-02-24 22:50:21 +0100merijn(~merijn@host-cl.cgnat-g.v4.dfn.nl) (Ping timeout: 265 seconds)
2026-02-24 22:50:15 +0100 <monochrom> After compiling with -O, the IO monad doesn't exist in the machine code.
2026-02-24 22:50:10 +0100 <mauke> printing is slow in C, too
2026-02-24 22:49:38 +0100 <EvanR> printing it out doesn't sound like the crunchy part
2026-02-24 22:49:28 +0100 <EvanR> this problem that separates a million integers into two sets that adds up to the same thing
2026-02-24 22:48:20 +0100 <EvanR> people mistake what's slow all the time, that's a haskell thing
2026-02-24 22:48:19 +0100Guest81(~Guest81@52.144.37.132)
2026-02-24 22:48:16 +0100 <monochrom> No, it says a lot about people having double standards.
2026-02-24 22:47:58 +0100 <newmind> why something as simple as "print out this list of numbers" might be slow
2026-02-24 22:47:33 +0100 <EvanR> it?
2026-02-24 22:47:07 +0100 <newmind> .o( but it does say a lot about haskell as a language/ecosystem that we're discussing it )
2026-02-24 22:46:06 +0100 <monochrom> I am unconvinced that (putStrLn . unwords . map show) is too slow. It's only 0.05 seconds on my laptop if you redirect to a file (which is the right thing to do if you're simulating an online autotester; if you let it go to a terminal, then the bottleneck is the terminal)
2026-02-24 22:45:47 +0100 <haskellbridge> <ijouw> I want this https://hackage-content.haskell.org/package/Boolean-0.2.4/docs/Data-Boolean.html#t:OrdB and then define a function nubOrd' :: (OrdB a, BooleanOf a ~ Bool) => [a] -> [a] ; (maybe i should just not reimplement everything...)